Known card feeding systems in a card handling device may include a support surface with pick-off roller(s) that are located within the support surface to remove one card at a time from the bottom of a vertically-oriented stack of cards. In this orientation, each card face is in a substantially horizontal plane with the face of a card contacting a back of an adjacent card. Such a gravity fed system moves individual cards from one stack into another stack of the card handling device to perform a shuffling operation. Cards may be inserted from the un-shuffled stack into the shuffled stack at a location that is determined by a random number generator (RNG), with the cards in the shuffled stack being gripped by a card gripper to create a gap at the desired location to insert the next card.
Early in the shuffling operation, there may only be a few cards on the elevator platform that holds the shuffled stack of cards. With only a few cards on the elevator platform, there may be some additional airspace (e.g., “fluff”) between cards. As more cards are added to the stack, the amount of fluff with those cards may decrease as the weight of the cards above them increases. For example, the first five cards on the stack may have a first thickness when they are the only cards on the elevator platform, but those same first five cards may have a second thickness smaller than the first thickness after more cards are added to the stack. As a result, the grip point for the card gripper to grip the cards for insertion may change over time as cards are added to the stack during a shuffling operation.
Conventional card handling devices have experienced difficulty in dealing with these different thicknesses within the stack. Conventional card handling devices simply determined a grip point based on the number of steps per card multiplied by the number of cards to be left on the platform. Such a method did not account for variations in the height of cards as the number of cards in the stack increased, and the cards on the bottom of the stack became more compressed. As a result, cards may be gripped at an incorrect location, causing cards to be inserted at the incorrect location during a shuffling operation. Thus, the output order of cards of the shuffled deck did not precisely match the virtual order prescribed by the RNG. While some amount of incorrect placement of cards may pass regulations for a “random” shuffle, at some point the shuffled set of cards may not pass the regulatory standard for randomness. The inventors have appreciated improvements to such card handling devices that may better account for these situations so that the shuffled deck may more closely follow the expected order generated by the RNG, and any bias in the shuffled deck may be reduced compared with conventional shuffling devices and methods.